SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '94425de6c356b4049bb21f501652f834e0ed26e1dd715121c4b38944e73b4852' 
  AND token = 'RUEURQcFLE4oG3iAuCW4edoGUGx81wxtOL+pSePfbFE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}